Regulation of vascular smooth muscle tone by caldesmon
Caldesmon is an actin-binding protein present in smooth muscle cells that also inhibits actin-activated myosin ATPase activity. To assess the possible role of caldesmon in the regulation of smooth contraction, we investigated the effects of synthetic peptides on force directly recorded from single h...
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Published in | The Journal of biological chemistry Vol. 267; no. 21; pp. 14555 - 14558 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
American Society for Biochemistry and Molecular Biology
25.07.1992
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Subjects | |
Online Access | Get full text |
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Summary: | Caldesmon is an actin-binding protein present in smooth muscle cells that also inhibits actin-activated myosin ATPase activity.
To assess the possible role of caldesmon in the regulation of smooth contraction, we investigated the effects of synthetic
peptides on force directly recorded from single hyperpermeable smooth muscle cells of ferret aorta and portal vein. GS17C,
a peptide that contains the residues from Gly651 to Ser667 of the caldesmon sequence plus an added cysteine at the C terminus,
binds calmodulin in a Ca(2+)-dependent manner and also binds to F-actin but does not inhibit actomyosin ATPase activity (Zhan,
Q., Wong, S.S., and Wang, C.-L.A. (1991) J. Biol. Chem. 266, 21810-21814). In cells in which Ca2+ was clamped at pCa 7.0,
GS17C induced a dose-dependent contraction (EC50 = 0.92 microM) in aorta cells, whereas it evoked little or no contraction
in portal vein cells. The GS17C-induced contraction in aorta cells was inhibited at higher Ca2+ concentrations (above pCa
6.6) and by pretreatment with calmodulin. Another peptide, C16AA, which contains the residues from Ala594 to Ala609 and does
not bind actin or calmodulin, did not induce contraction. Our results strongly suggest that GS17C induces contraction by the
displacement of the inhibitory region of endogenous caldesmon and, furthermore, that caldesmon present in these smooth muscle
cells regulates contraction by providing a basal resting inhibition of vascular tone. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/s0021-9258(18)42075-3 |